Powder core, manufacturing method of powder core, inductor including powder core, and electronic/electric device having inductor mounted therein

Abstract

A powder core includes: a powder of a crystalline magnetic material; and a powder of an amorphous magnetic material, in which a median diameter D50A of the powder of the amorphous magnetic material is 15 μm or less, and satisfies the expression: 1≤D50A/D50C≤3.5 with respect to a median diameter D50C of the powder of the crystalline magnetic material.

What is claimed is: 
     
       1. A powder core comprising:
 an amorphous magnetic material powder having a first median diameter D50A equal to or less than 7 μm; and 
 a crystalline magnetic material powder having a second median diameter D50C, 
 wherein the first median diameter D50A and the second median diameter D50C satisfy:
   1≤ D 50 A/D 50 C≤ 3.5,
 
 
 and wherein a first mixing ratio which is a mass ratio of the crystalline magnetic material powder content of the powder core to a sum of the crystalline magnetic material powder content and the amorphous magnetic material powder content in the powder core is equal to or greater than 20 mass % and equal to or smaller than 40 mass %. 
 
     
     
       2. The powder core according to  claim 1 ,
 wherein the first median diameter D50A and the second median diameter D50C satisfy:
   1.2≤ D 50 A/D 50 C≤ 2.5.
 
 
 
     
     
       3. The powder core according to  claim 1 ,
 wherein the crystalline magnetic material contains one material or two or more materials selected from the group consisting of a Fe—Si—Cr alloy, a Fe—Ni alloy, a Fe—Co alloy, a Fe—V alloy, a Fe—Al alloy, a Fe—Si alloy, a Fe—Si—Al alloy, carbonyl iron, and pure iron. 
 
     
     
       4. The powder core according to  claim 3 ,
 wherein the crystalline magnetic material is made of the Fe—Si—Cr alloy. 
 
     
     
       5. The powder core according to  claim 1 ,
 wherein the amorphous magnetic material contains one material or two or more materials selected from the group consisting of a Fe—Si—B alloy, a Fe—P—C alloy, and a Co—Fe—Si—B alloy. 
 
     
     
       6. The powder core according to  claim 5 ,
 wherein the amorphous magnetic material is made of the Fe—P—C alloy. 
 
     
     
       7. The powder core according to  claim 1 ,
 wherein the crystalline magnetic material powder has surfaces subjected to an insulation treatment. 
 
     
     
       8. The powder core according to  claim 1 , further comprising:
 a binding component which binds the crystalline magnetic material powder and the amorphous magnetic material powder to other materials contained in the powder core. 
 
     
     
       9. The powder core according to  claim 8 ,
 wherein the binding component contains a resin-based material. 
 
     
     
       10. A method for manufacturing the powder core according to  claim 9 , comprising:
 obtaining a molded product by a molding treatment including pressure molding a mixture containing the crystalline magnetic material powder, the amorphous magnetic material powder, and the binding component containing the resin-based material. 
 
     
     
       11. The method according to  claim 10 ,
 wherein the molded product is the powder core. 
 
     
     
       12. The method according to  claim 10 , further comprising:
 performing a heat treatment of heating the molded product, thereby obtaining the powder core. 
 
     
     
       13. An inductor comprising:
 the powder core according to  claim 1 ; 
 a coil configured to generate an induced magnetic field by a current flowing therethrough; and 
 connection terminals connected to respective ends of the coil so as to supply the current to the coil, 
 wherein the powder core is disposed such that at least a part of the powder core is positioned in the induced magnetic field generated by the current flowing through the coil.